Method of and apparatus for straining the waste water in paper-mills, wood-pulp factories, and the like.



No. 898,212. PATENTED SEPT. 8, 1908. H. GAAR-A & E. HEM.

METHOD OF AND APPARATUS FOR STRAINING THE WASTE WATER IN PAPER-MILLS,WOOD PULP FAGTORIES, AND THE LIKE. APPLIOATIOH FILED APB.20,1908.

through the pores or UNITED STATES PATENT OFFICE.

HALVOR GAARA AND EILIF HEM, OF TELEMARKEN, NORWAY.

METHOD OF APPARATUS FQR STRAINING THE WASTE WATER IN PAPER-MILLS, AWOOD-PULP FAOTORIES, AND THE LIKE.

Patented Sept. 8, 1908.

Application filed April 20, 1908. Serial N 0. 428,249.

To all whom it may concern:

Be it known that we, HALVOR. GAARA and EILIF HEM, subjects of the Kingof Norway,

both residing at Telemarken, Norway, have invented certain new anduseful ments in the Methods of and A aratus for straining the WasteWater in aper-Mills, Wood-Pulp Factories, and the Like; and we do herebydeclare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled which it appertains tomake and use the same, reference being had to the accompanyin drawings,and to letters or figures of re erence marked thereon, which form a partof this specification.

Our invention consists in a method of and apparatus for straining thewaste water in papermills, wood pul actories and the like.

hen recovering t e finely divided short fibers contained in the wastewater in paper mills, wood pul factories and the like, by means of thewe known cylindric strainers a considerable quantity 'of the fiberspasses qpenings of the strainer y using a very fine Improveoloth and islost. strainer cloth, the loss less, but on the other hand the drawbackthen arises that too fine cloths are very quickly worn out and the finepores of the same are choked up already after short use.

It has been proposed in order to remedy these defects, eriodically tosupply asbestos fibers to the tering apparatus, 1n order that suchasbestos fibers may make the strainer of the drum tighter. A periodicalsupply of long fibered stufi is not, however, applicable in theapparatus employed for o earing the waste water in paper mills, woodpulp mills and the like, owin to the considerable quantities of water toe cleared. If a considerable quantity of water is to be cleared by theseapparatus, it is necessary that the mass deposited on the cylindershould be continually removed from the same; but if this is done, thelong fibers will then be simultaneously removed; for an efiicient meansof removing the short fibers without simultaneously removing thesubjacent filter layer, which consists of long fibers, is not yet known.The said drawbacks are avoided by the present method according to whicha strainer is employed for recovering the short-fibered material,long-fibered material being continually fed to said strainer in such away as in the art to of material would be v to enable it to deposititself on the continually rotating cylinder, before the short-fiberedmaterial is filtered through the filter layer thus formed.

The arrangement according to the present invention consists in providingalong the whole length of the cylinder, where the strainer passes downinto the water, a separate space, into which relatively long-fiberedmaterial is continually fed, for the purpose of causing this mass todeposit itself on the cloth in the said compartment and to form, on theouter side of the cloth, a filter layer, which prevents the relativelyshort-fibered mass, contained in the liquid to be cleared, from passingthrough the strainer during the further movement of the same through thecontainer.

In the accom anying drawing two forms of strainer emgodying theinvention are shown in section (Figures 1 and 2).

1 is the straining cylinder of the apparatus moving in the direction ofthe arrow; 2 is the container, in which the cylinder rotates; 3 is theinlet channel for the exhaust water to be cleared.

The relatively long-fibered mass is passed from a conduit 4 to aseparate compartment 5, which is located where the clean strainer clothpasses into the liquid. In this compartment the long-fibered material,during the rotation of the drum, is continually deposited unimpededbythe short-fibered material outside the said compartment. In spite ofbeing, without interruption, continuously filtered, the latter material,therefore, only gets into contact with long-fibrous material alreadycompletely de osited, whereby loss of short-fibrous materia is avoided,and the use of comparatively coarse-meshed strainer cloth renderedpossible. The inlet channel 3 can of course, as shown'in Fig. 2, also belocated at the opposite side, in which case the wall 2, as shown in thedrawing may be disposed so near the cylinder at the op 0- site si e asto replace the screen 6 provided in Fig. 1 to form a wall of compartment5. A certain amount of fibers of the lon fibered mass fed to the comartment 5 will always ass through the clot before the filter layer hasbeen ready formed. In order that such fibers may not be lost, theapparatus, accordg to the present invention,'1s provided with a cylinderof the known type, that conducts the water passing through the cylindercloth and containing the material in question, away from the clean watersubsequently discharged.

In apparatus designed for straining the exhaust water from wood pulmills, the longfibered material may be 0 tained from the inlet channelto the paste boardmachines or the decker machines. In a aper millcombined with a wood pulp m' or a cellulose factory the long-fibrousmass to be supplied to the clearing apparatus for the water dischargedfrom the paper machinesis obtained from the pulp mil or the cellulosefactory.

If'the strainer for any leng h of time operates without being inspecteand the apparatus in conse uence hereof for some reason or other shoulstop, the material would be lost, owing to the long-fibered material'sflowing over the container. To, avoid a loss of material occasionedhereby an overflow channel 7 is provided above the normal water level,through which channel the long-fibered material, when required, may flowout of the container 2 and, by way of a conduit 11 or the like, bedischarged into the pulp containing water 9 flowin from the strainer orclearing apparatus. he mass deposited on the strainer cloth is carriedofi in a well-known manner by means of a roller and a scraping device 8or by other known means. The mass flowing from the roller 8 ma in somecases, as shown in the drawing, be ischarged from the container at 9together with the water, and in a manner previously known be returned tothe paste board machines or the decker machines to be utilized in thesame. 10 is a screen that may be variously dis osed. It is designed toprevent the mass owing from the roller from sinking to the bottom.

Claims.

1. The method of straining the waste water in aper factories, pulpfactories and the like, w ich consists in irectingto the strainmgsurface of a straining apparatus independently of and simultaneouslywith the water to be strained a quantity of longfibered ulp so as tocontinually form a layer of longbered material on the straining surfacebefore the latter comes into contact with the water to be strained, andremovin it contmuously together with the short fi ers depositedthereupon.

2. A strainer comprising a strainer body and a container, means forconducting the water to be strained to the container, means forconducting long-fibered straining material to the containersimultaneously with but inde endent of the water to be strained and indirect contact with the straining surface,

HALVOR GAARA. EILIF HEM.

Witnesses:

HENRY Bonnnwron, MICHAEL ALGER.

